FOR ADVANCED PROGRAMMERS:
MEMORY LOCATIONS USED BY THE GRAPPLER
The Grappler Interface uses those RAM locations set aside for its particular slot and the slot scratchpad area common to all slots. The ROM is turned on using the standard ROM expansion protocol and resides in locations $C8ØØ to $CFFF. The entry points and the various RAM variables are listed below (N=Slot number):
Cold Entry | = $CNØØ |
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Warm Entry | = $CNØ2 |
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Left Margin | = $478 | + $ØN |
Right Margin | = $678 | + $ØN |
Line Length | = $578 | + $ØN |
Page Length | = $5F8 | + $ØN |
Character Counter | = $4F8 | + $ØN |
Line Counter | = $6F8 | + $ØN |
Current Cmd. Char. | = $778 | + $ØN |
Text Flags | = $7F8 | + $ØN |
Text Flag Bit Representations: (Bit 7 - Output high order bit) (Bit 6 - Video turned on)
(Bit 5 - LF after a CR) (Bit 4 — Bell on)